xref: /openbmc/qemu/docs/sphinx/qapi_domain.py (revision 8b77f8d5730003d868b5748af5438c43d17f8c3a)
1"""
2QAPI domain extension.
3"""
4
5from __future__ import annotations
6
7from typing import (
8    TYPE_CHECKING,
9    AbstractSet,
10    Any,
11    Dict,
12    Iterable,
13    List,
14    NamedTuple,
15    Optional,
16    Tuple,
17    cast,
18)
19
20from docutils import nodes
21from docutils.parsers.rst import directives
22
23from compat import KeywordNode, SpaceNode
24from sphinx import addnodes
25from sphinx.addnodes import desc_signature, pending_xref
26from sphinx.directives import ObjectDescription
27from sphinx.domains import (
28    Domain,
29    Index,
30    IndexEntry,
31    ObjType,
32)
33from sphinx.locale import _, __
34from sphinx.roles import XRefRole
35from sphinx.util import logging
36from sphinx.util.docfields import Field, GroupedField, TypedField
37from sphinx.util.nodes import make_id, make_refnode
38
39
40if TYPE_CHECKING:
41    from docutils.nodes import Element, Node
42
43    from sphinx.application import Sphinx
44    from sphinx.builders import Builder
45    from sphinx.environment import BuildEnvironment
46    from sphinx.util.typing import OptionSpec
47
48logger = logging.getLogger(__name__)
49
50
51class ObjectEntry(NamedTuple):
52    docname: str
53    node_id: str
54    objtype: str
55    aliased: bool
56
57
58class QAPIXRefRole(XRefRole):
59
60    def process_link(
61        self,
62        env: BuildEnvironment,
63        refnode: Element,
64        has_explicit_title: bool,
65        title: str,
66        target: str,
67    ) -> tuple[str, str]:
68        refnode["qapi:module"] = env.ref_context.get("qapi:module")
69
70        # Cross-references that begin with a tilde adjust the title to
71        # only show the reference without a leading module, even if one
72        # was provided. This is a Sphinx-standard syntax; give it
73        # priority over QAPI-specific type markup below.
74        hide_module = False
75        if target.startswith("~"):
76            hide_module = True
77            target = target[1:]
78
79        # Type names that end with "?" are considered optional
80        # arguments and should be documented as such, but it's not
81        # part of the xref itself.
82        if target.endswith("?"):
83            refnode["qapi:optional"] = True
84            target = target[:-1]
85
86        # Type names wrapped in brackets denote lists. strip the
87        # brackets and remember to add them back later.
88        if target.startswith("[") and target.endswith("]"):
89            refnode["qapi:array"] = True
90            target = target[1:-1]
91
92        if has_explicit_title:
93            # Don't mess with the title at all if it was explicitly set.
94            # Explicit title syntax for references is e.g.
95            # :qapi:type:`target <explicit title>`
96            # and this explicit title overrides everything else here.
97            return title, target
98
99        title = target
100        if hide_module:
101            title = target.split(".")[-1]
102
103        return title, target
104
105
106# Alias for the return of handle_signature(), which is used in several places.
107# (In the Python domain, this is Tuple[str, str] instead.)
108Signature = str
109
110
111class QAPIDescription(ObjectDescription[Signature]):
112    """
113    Generic QAPI description.
114
115    This is meant to be an abstract class, not instantiated
116    directly. This class handles the abstract details of indexing, the
117    TOC, and reference targets for QAPI descriptions.
118    """
119
120    def handle_signature(self, sig: str, signode: desc_signature) -> Signature:
121        # Do nothing. The return value here is the "name" of the entity
122        # being documented; for QAPI, this is the same as the
123        # "signature", which is just a name.
124
125        # Normally this method must also populate signode with nodes to
126        # render the signature; here we do nothing instead - the
127        # subclasses will handle this.
128        return sig
129
130    def get_index_text(self, name: Signature) -> Tuple[str, str]:
131        """Return the text for the index entry of the object."""
132
133        # NB: this is used for the global index, not the QAPI index.
134        return ("single", f"{name} (QMP {self.objtype})")
135
136    def add_target_and_index(
137        self, name: Signature, sig: str, signode: desc_signature
138    ) -> None:
139        # name is the return value of handle_signature.
140        # sig is the original, raw text argument to handle_signature.
141        # For QAPI, these are identical, currently.
142
143        assert self.objtype
144
145        # If we're documenting a module, don't include the module as
146        # part of the FQN.
147        modname = ""
148        if self.objtype != "module":
149            modname = self.options.get(
150                "module", self.env.ref_context.get("qapi:module")
151            )
152        fullname = (modname + "." if modname else "") + name
153
154        node_id = make_id(
155            self.env, self.state.document, self.objtype, fullname
156        )
157        signode["ids"].append(node_id)
158
159        self.state.document.note_explicit_target(signode)
160        domain = cast(QAPIDomain, self.env.get_domain("qapi"))
161        domain.note_object(fullname, self.objtype, node_id, location=signode)
162
163        if "no-index-entry" not in self.options:
164            arity, indextext = self.get_index_text(name)
165            assert self.indexnode is not None
166            if indextext:
167                self.indexnode["entries"].append(
168                    (arity, indextext, node_id, "", None)
169                )
170
171    def _object_hierarchy_parts(
172        self, sig_node: desc_signature
173    ) -> Tuple[str, ...]:
174        if "fullname" not in sig_node:
175            return ()
176        modname = sig_node.get("module")
177        fullname = sig_node["fullname"]
178
179        if modname:
180            return (modname, *fullname.split("."))
181
182        return tuple(fullname.split("."))
183
184    def _toc_entry_name(self, sig_node: desc_signature) -> str:
185        # This controls the name in the TOC and on the sidebar.
186
187        # This is the return type of _object_hierarchy_parts().
188        toc_parts = cast(Tuple[str, ...], sig_node.get("_toc_parts", ()))
189        if not toc_parts:
190            return ""
191
192        config = self.env.app.config
193        *parents, name = toc_parts
194        if config.toc_object_entries_show_parents == "domain":
195            return sig_node.get("fullname", name)
196        if config.toc_object_entries_show_parents == "hide":
197            return name
198        if config.toc_object_entries_show_parents == "all":
199            return ".".join(parents + [name])
200        return ""
201
202
203class QAPIObject(QAPIDescription):
204    """
205    Description of a generic QAPI object.
206
207    It's not used directly, but is instead subclassed by specific directives.
208    """
209
210    # Inherit some standard options from Sphinx's ObjectDescription
211    option_spec: OptionSpec = (  # type:ignore[misc]
212        ObjectDescription.option_spec.copy()
213    )
214    option_spec.update(
215        {
216            # Borrowed from the Python domain:
217            "module": directives.unchanged,  # Override contextual module name
218            # These are QAPI originals:
219            "since": directives.unchanged,
220        }
221    )
222
223    doc_field_types = [
224        # :feat name: descr
225        GroupedField(
226            "feature",
227            label=_("Features"),
228            names=("feat",),
229            can_collapse=False,
230        ),
231    ]
232
233    def get_signature_prefix(self) -> List[nodes.Node]:
234        """Return a prefix to put before the object name in the signature."""
235        assert self.objtype
236        return [
237            KeywordNode("", self.objtype.title()),
238            SpaceNode(" "),
239        ]
240
241    def get_signature_suffix(self) -> List[nodes.Node]:
242        """Return a suffix to put after the object name in the signature."""
243        ret: List[nodes.Node] = []
244
245        if "since" in self.options:
246            ret += [
247                SpaceNode(" "),
248                addnodes.desc_sig_element(
249                    "", f"(Since: {self.options['since']})"
250                ),
251            ]
252
253        return ret
254
255    def handle_signature(self, sig: str, signode: desc_signature) -> Signature:
256        """
257        Transform a QAPI definition name into RST nodes.
258
259        This method was originally intended for handling function
260        signatures. In the QAPI domain, however, we only pass the
261        definition name as the directive argument and handle everything
262        else in the content body with field lists.
263
264        As such, the only argument here is "sig", which is just the QAPI
265        definition name.
266        """
267        modname = self.options.get(
268            "module", self.env.ref_context.get("qapi:module")
269        )
270
271        signode["fullname"] = sig
272        signode["module"] = modname
273        sig_prefix = self.get_signature_prefix()
274        if sig_prefix:
275            signode += addnodes.desc_annotation(
276                str(sig_prefix), "", *sig_prefix
277            )
278        signode += addnodes.desc_name(sig, sig)
279        signode += self.get_signature_suffix()
280
281        return sig
282
283
284class QAPICommand(QAPIObject):
285    """Description of a QAPI Command."""
286
287    doc_field_types = QAPIObject.doc_field_types.copy()
288    doc_field_types.extend(
289        [
290            # :arg TypeName ArgName: descr
291            TypedField(
292                "argument",
293                label=_("Arguments"),
294                names=("arg",),
295                can_collapse=False,
296            ),
297            # :error: descr
298            Field(
299                "error",
300                label=_("Errors"),
301                names=("error", "errors"),
302                has_arg=False,
303            ),
304            # :return TypeName: descr
305            GroupedField(
306                "returnvalue",
307                label=_("Return"),
308                names=("return",),
309                can_collapse=True,
310            ),
311        ]
312    )
313
314
315class QAPIModule(QAPIDescription):
316    """
317    Directive to mark description of a new module.
318
319    This directive doesn't generate any special formatting, and is just
320    a pass-through for the content body. Named section titles are
321    allowed in the content body.
322
323    Use this directive to create entries for the QAPI module in the
324    global index and the QAPI index; as well as to associate subsequent
325    definitions with the module they are defined in for purposes of
326    search and QAPI index organization.
327
328    :arg: The name of the module.
329    :opt no-index: Don't add cross-reference targets or index entries.
330    :opt no-typesetting: Don't render the content body (but preserve any
331       cross-reference target IDs in the squelched output.)
332
333    Example::
334
335       .. qapi:module:: block-core
336          :no-index:
337          :no-typesetting:
338
339          Lorem ipsum, dolor sit amet ...
340    """
341
342    def run(self) -> List[Node]:
343        modname = self.arguments[0].strip()
344        self.env.ref_context["qapi:module"] = modname
345        ret = super().run()
346
347        # ObjectDescription always creates a visible signature bar. We
348        # want module items to be "invisible", however.
349
350        # Extract the content body of the directive:
351        assert isinstance(ret[-1], addnodes.desc)
352        desc_node = ret.pop(-1)
353        assert isinstance(desc_node.children[1], addnodes.desc_content)
354        ret.extend(desc_node.children[1].children)
355
356        # Re-home node_ids so anchor refs still work:
357        node_ids: List[str]
358        if node_ids := [
359            node_id
360            for el in desc_node.children[0].traverse(nodes.Element)
361            for node_id in cast(List[str], el.get("ids", ()))
362        ]:
363            target_node = nodes.target(ids=node_ids)
364            ret.insert(1, target_node)
365
366        return ret
367
368
369class QAPIIndex(Index):
370    """
371    Index subclass to provide the QAPI definition index.
372    """
373
374    # pylint: disable=too-few-public-methods
375
376    name = "index"
377    localname = _("QAPI Index")
378    shortname = _("QAPI Index")
379
380    def generate(
381        self,
382        docnames: Optional[Iterable[str]] = None,
383    ) -> Tuple[List[Tuple[str, List[IndexEntry]]], bool]:
384        assert isinstance(self.domain, QAPIDomain)
385        content: Dict[str, List[IndexEntry]] = {}
386        collapse = False
387
388        # list of all object (name, ObjectEntry) pairs, sorted by name
389        # (ignoring the module)
390        objects = sorted(
391            self.domain.objects.items(),
392            key=lambda x: x[0].split(".")[-1].lower(),
393        )
394
395        for objname, obj in objects:
396            if docnames and obj.docname not in docnames:
397                continue
398
399            # Strip the module name out:
400            objname = objname.split(".")[-1]
401
402            # Add an alphabetical entry:
403            entries = content.setdefault(objname[0].upper(), [])
404            entries.append(
405                IndexEntry(
406                    objname, 0, obj.docname, obj.node_id, obj.objtype, "", ""
407                )
408            )
409
410            # Add a categorical entry:
411            category = obj.objtype.title() + "s"
412            entries = content.setdefault(category, [])
413            entries.append(
414                IndexEntry(objname, 0, obj.docname, obj.node_id, "", "", "")
415            )
416
417        # alphabetically sort categories; type names first, ABC entries last.
418        sorted_content = sorted(
419            content.items(),
420            key=lambda x: (len(x[0]) == 1, x[0]),
421        )
422        return sorted_content, collapse
423
424
425class QAPIDomain(Domain):
426    """QAPI language domain."""
427
428    name = "qapi"
429    label = "QAPI"
430
431    # This table associates cross-reference object types (key) with an
432    # ObjType instance, which defines the valid cross-reference roles
433    # for each object type.
434    object_types: Dict[str, ObjType] = {
435        "module": ObjType(_("module"), "mod", "any"),
436        "command": ObjType(_("command"), "cmd", "any"),
437    }
438
439    # Each of these provides a rST directive,
440    # e.g. .. qapi:module:: block-core
441    directives = {
442        "module": QAPIModule,
443        "command": QAPICommand,
444    }
445
446    # These are all cross-reference roles; e.g.
447    # :qapi:cmd:`query-block`. The keys correlate to the names used in
448    # the object_types table values above.
449    roles = {
450        "mod": QAPIXRefRole(),
451        "cmd": QAPIXRefRole(),
452        "any": QAPIXRefRole(),  # reference *any* type of QAPI object.
453    }
454
455    # Moved into the data property at runtime;
456    # this is the internal index of reference-able objects.
457    initial_data: Dict[str, Dict[str, Tuple[Any]]] = {
458        "objects": {},  # fullname -> ObjectEntry
459    }
460
461    # Index pages to generate; each entry is an Index class.
462    indices = [
463        QAPIIndex,
464    ]
465
466    @property
467    def objects(self) -> Dict[str, ObjectEntry]:
468        ret = self.data.setdefault("objects", {})
469        return ret  # type: ignore[no-any-return]
470
471    def note_object(
472        self,
473        name: str,
474        objtype: str,
475        node_id: str,
476        aliased: bool = False,
477        location: Any = None,
478    ) -> None:
479        """Note a QAPI object for cross reference."""
480        if name in self.objects:
481            other = self.objects[name]
482            if other.aliased and aliased is False:
483                # The original definition found. Override it!
484                pass
485            elif other.aliased is False and aliased:
486                # The original definition is already registered.
487                return
488            else:
489                # duplicated
490                logger.warning(
491                    __(
492                        "duplicate object description of %s, "
493                        "other instance in %s, use :no-index: for one of them"
494                    ),
495                    name,
496                    other.docname,
497                    location=location,
498                )
499        self.objects[name] = ObjectEntry(
500            self.env.docname, node_id, objtype, aliased
501        )
502
503    def clear_doc(self, docname: str) -> None:
504        for fullname, obj in list(self.objects.items()):
505            if obj.docname == docname:
506                del self.objects[fullname]
507
508    def merge_domaindata(
509        self, docnames: AbstractSet[str], otherdata: Dict[str, Any]
510    ) -> None:
511        for fullname, obj in otherdata["objects"].items():
512            if obj.docname in docnames:
513                # Sphinx's own python domain doesn't appear to bother to
514                # check for collisions. Assert they don't happen and
515                # we'll fix it if/when the case arises.
516                assert fullname not in self.objects, (
517                    "bug - collision on merge?"
518                    f" {fullname=} {obj=} {self.objects[fullname]=}"
519                )
520                self.objects[fullname] = obj
521
522    def find_obj(
523        self, modname: str, name: str, typ: Optional[str]
524    ) -> list[tuple[str, ObjectEntry]]:
525        """
526        Find a QAPI object for "name", perhaps using the given module.
527
528        Returns a list of (name, object entry) tuples.
529
530        :param modname: The current module context (if any!)
531                        under which we are searching.
532        :param name: The name of the x-ref to resolve;
533                     may or may not include a leading module.
534        :param type: The role name of the x-ref we're resolving, if provided.
535                     (This is absent for "any" lookups.)
536        """
537        if not name:
538            return []
539
540        names: list[str] = []
541        matches: list[tuple[str, ObjectEntry]] = []
542
543        fullname = name
544        if "." in fullname:
545            # We're searching for a fully qualified reference;
546            # ignore the contextual module.
547            pass
548        elif modname:
549            # We're searching for something from somewhere;
550            # try searching the current module first.
551            # e.g. :qapi:cmd:`query-block` or `query-block` is being searched.
552            fullname = f"{modname}.{name}"
553
554        if typ is None:
555            # type isn't specified, this is a generic xref.
556            # search *all* qapi-specific object types.
557            objtypes: List[str] = list(self.object_types)
558        else:
559            # type is specified and will be a role (e.g. obj, mod, cmd)
560            # convert this to eligible object types (e.g. command, module)
561            # using the QAPIDomain.object_types table.
562            objtypes = self.objtypes_for_role(typ, [])
563
564        if name in self.objects and self.objects[name].objtype in objtypes:
565            names = [name]
566        elif (
567            fullname in self.objects
568            and self.objects[fullname].objtype in objtypes
569        ):
570            names = [fullname]
571        else:
572            # exact match wasn't found; e.g. we are searching for
573            # `query-block` from a different (or no) module.
574            searchname = "." + name
575            names = [
576                oname
577                for oname in self.objects
578                if oname.endswith(searchname)
579                and self.objects[oname].objtype in objtypes
580            ]
581
582        matches = [(oname, self.objects[oname]) for oname in names]
583        if len(matches) > 1:
584            matches = [m for m in matches if not m[1].aliased]
585        return matches
586
587    def resolve_xref(
588        self,
589        env: BuildEnvironment,
590        fromdocname: str,
591        builder: Builder,
592        typ: str,
593        target: str,
594        node: pending_xref,
595        contnode: Element,
596    ) -> nodes.reference | None:
597        modname = node.get("qapi:module")
598        matches = self.find_obj(modname, target, typ)
599
600        if not matches:
601            return None
602
603        if len(matches) > 1:
604            logger.warning(
605                __("more than one target found for cross-reference %r: %s"),
606                target,
607                ", ".join(match[0] for match in matches),
608                type="ref",
609                subtype="qapi",
610                location=node,
611            )
612
613        name, obj = matches[0]
614        return make_refnode(
615            builder, fromdocname, obj.docname, obj.node_id, contnode, name
616        )
617
618    def resolve_any_xref(
619        self,
620        env: BuildEnvironment,
621        fromdocname: str,
622        builder: Builder,
623        target: str,
624        node: pending_xref,
625        contnode: Element,
626    ) -> List[Tuple[str, nodes.reference]]:
627        results: List[Tuple[str, nodes.reference]] = []
628        matches = self.find_obj(node.get("qapi:module"), target, None)
629        for name, obj in matches:
630            rolename = self.role_for_objtype(obj.objtype)
631            assert rolename is not None
632            role = f"qapi:{rolename}"
633            refnode = make_refnode(
634                builder, fromdocname, obj.docname, obj.node_id, contnode, name
635            )
636            results.append((role, refnode))
637        return results
638
639
640def setup(app: Sphinx) -> Dict[str, Any]:
641    app.setup_extension("sphinx.directives")
642    app.add_domain(QAPIDomain)
643
644    return {
645        "version": "1.0",
646        "env_version": 1,
647        "parallel_read_safe": True,
648        "parallel_write_safe": True,
649    }
650